Digital goods (e.g., software products, data, content, etc.) are often distributed to consumers via fixed computer readable media, such as a compact disc (CD-ROM), digital versatile disc (DVD), soft magnetic diskette, or hard magnetic disk (e.g., a preloaded hard drive). More recently, more and more content is being delivered in digital form online over private and public networks, such as Intranets and the Internet. Online delivery improves timeliness and convenience for the user, as well as reduces delivery costs for a publisher or developers. Unfortunately, these worthwhile attributes are often outweighed in the minds of the publishers/developers by a corresponding disadvantage that online information delivery makes it relatively easy to obtain pristine digital content and to pirate the content at the expense and harm of the publisher/developer.
One concern of the publisher/developer is the ability to check digital content, after distribution, for alteration. Such checking, is often referred to as SRI (Software Resistance to Interference). The desire to check for such alterations can vary (e.g., to ensure that the content continues to operate as intended by the publisher/developer, to protect against improper copying, etc.).
The unusual property of content is that the publisher/developer (or reseller) gives or sells the content to a client, but continues to restrict rights to use the content even after the content is under the sole physical control of the client. For instance, a software developer typically sells a limited license in a software product that permits a user to load and run the software product on one or more machines (depending upon the license terms), as well as make a back up copy. The user is typically not permitted to make unlimited copies or redistribute the software to others.
These scenarios reveal a peculiar arrangement. The user that possesses the digital bits often does not have full rights to their use; instead, the provider retains at least some of the rights. In a very real sense, the legitimate user of a computer can be an adversary of the data or content provider.
One of the uses for SRI is to provide “digital rights management” (or “DRM”) protection to prevent unauthorized distribution of, copying and/or illegal operation of, or access to the digital goods. An ideal digital goods distribution system would substantially prevent unauthorized distribution/use of the digital goods. Digital rights management is fast becoming a central requirement if online commerce is to continue its rapid growth. Content providers and the computer industry must quickly address technologies and protocols for ensuring that digital goods are properly handled in accordance with the rights granted by the developer/publisher. If measures are not taken, traditional content providers may be put out of business by widespread theft or, more likely, will refuse altogether to deliver content online.
Various DRM techniques have been developed and employed in an attempt to thwart potential pirates from illegally copying or otherwise distributing the digital goods to others. For example, one DRM technique includes requiring the consumer to insert the original CD-ROM or DVD for verification prior to enabling the operation of a related copy of the digital good. Unfortunately, this DRM technique typically places an unwelcome burden on the honest consumer, especially those concerned with speed and productivity. Moreover, such techniques are impracticable for digital goods that are site licensed, such as software products that are licensed for use by several computers, and/or for digital goods that are downloaded directly to a computer. Additionally, it is not overly difficult for unscrupulous individuals/organizations to produce working pirated copies of the CD-ROM.
Another DRM technique includes requiring or otherwise encouraging the consumer to register the digital good with the provider, for example, either through the mail or online via the Internet or a direct connection. Thus, the digital good may require the consumer to enter a registration code before allowing the digital good to be fully operational or the digital content to be fully accessed. Unfortunately, such DRM techniques are not always effective since unscrupulous individuals/organizations need only break through or otherwise undermine the DRM protections in a single copy of the digital good. Once broken, copies of the digital good can be illegally distributed, hence such DRM techniques are considered to be Break-Once, Run-Everywhere (BORE) susceptible. Various different techniques can be used to defeat BORE, such as per-user software individualization, watermarks, etc. However, a malicious user may still be able to identify and remove from the digital good these various protections.
Accordingly, there remains a need for a technique that addresses the concerns of the publisher/developer, allowing alteration of the digital content to be identified to assist in protecting the content from many of the known and common attacks, but does not impose unnecessary and burdensome requirements on legitimate users.